This invention relates to a steering axle. In particular the invention is directed to a driven steering axle. The invention concerns shafts for the axle having a wheelhub or a planetary reduction gear in the hub.
Driven steering shafts for axles include shafts with a planetary reduction gear in the wheelhub, and those with a boot partially covering a shaft joint between a driven shaft and the steering shaft.
In known arrangements power is transmitted from a differential outwardly through a driven shaft or axle shaft, and the ends of the driven shaft or axle shaft are inserted into the inwardly facing steering joint component which is in turn securely connected to the steering shaft. The steering shaft drives the wheelhub or the inner gear of a planetary gearbox located within the wheelhub. The shaft joint includes a universal joint, or preferably, a constant velocity joint, when viewed from its greatest diameter towards the wheelhub, and is enclosed in a housing and packed with grease. The seal of the steering shaft is achieved with a boot which is attached at the greatest diameter on the housing for the shaft joint and at its smallest diameter on the steering shaft.
This arrangement has the disadvantage in that the relatively well protected side of the shaft joint, namely, the side facing the wheelhub, is in a housing, while the boot, which extends in a direction towards the vehicle center of the vehicle, is relatively unprotected and is consequently susceptible to damage under severe operating conditions.
Considerable labor is required to replace the boot which is normally constructed of rubber, and which is no longer serviceable due to damage or age. The same problems arise when a universal joint or a constant velocity joint requires replacement. In both cases the wheel, wheelhub, and the entire steering housing must be removed before the steering shaft with the shaft joint or even the boot can be replaced. When the small diameter end of the boot is reattached to the shaft, the entire steering shaft must be removed. Furthermore, in the case of a planetary steering shaft, the oil needs to be drained and the entire planetary unit has to be removed.
In view of this there is a need to provide a steering axle, especially for a planetary steering shaft, which minimizes the above disadvantages, and which protects the boot from external damage and which requires reduced effort for replacing the boot or the shaft joint.